For example (from wikipedia) "The giant panda...is a favorite animal in popular culture."

Esotericism, although nominally the opposite of popular, may be part of popular culture, for example, freemasonry.

Popular culture is constantly changing and is specific to place and time. One may speak of mainstream popular culture, thus contemplating subsets, "Kraftwerk have impinged on mainstream popular culture to the extent that they have been referenced in The Simpsons and Father Ted."